LEP and obesity due to melanocortin 4 receptor deficiency: We hypothesized that in human obesity, a link might exist between changed circulating levels of vasoactive adipokines and ET-1-dependent vasoconstriction; Methods: We compared plasma concentrations of selected adipokines (Luminex assay) and the vasoactive response to blockade of endothelin type A receptors (ETA) by BQ-123 (strain-gauge plethysmography) in lean and obese individuals; Results: Plasma levels of adipokines with deleterious vascular actions, such as chemerin, visfatin, adipsin, and leptin, were higher in obese than in lean subjects (all p < 0.05).